@CHARSET "UTF-8";
		.btn{
  			width: 100%;
  			height: 100%;
  			font-weight: bold;
  			font-size: 20;
  		}
  		
  		.textview{
  			width: 100%;
  			height: 100%;
  			font-weight: bold;
  			font-size: 30;
  		}
  		
  		
  		
  		.btn:HOVER{
  			background: #0000dd;
  		}
  		
  		#calculator{
  			font-size：黑体;
            margin: auto;
            border: solid 1px #000000;
            height: 400px;
            width: 300px;
            text-align: center;
    }